There are different types of concrete walls commonly used in the civil work practice. Said walls are either prefabricated or realized with modular concrete elements pre-formed in a factory and subsequently masoned in a building yard.
The present invention is not part of the building technologies mentioned above, but relates to the building technology of the concrete walls cast in situ.
The concrete casting technique is known for a long time and is generally based on the use of a formwork, the purpose of which is to contain the concrete until it is sufficiently hardened, so as to get the appropriate structural resistance characteristics.
The purpose of a formwork is twofold: its first function is to give the desired geometric shape and dimensions to the casting, and the second one consists of the mechanical function of withstanding the hydrostatic pressure exerted by the liquid concrete and the solidification vibrations. Formworks can be classified into two main categories as follow: re-usable formworks, which generally consist of flat panels made of wood, metal, or other suitable materials, and disposable formworks.
Whenever a material is cast into a formwork that shall not be subsequently removed, but shall remain integral to the hardened cement, then we speak about disposable formwork.
In the building technique there are many examples of structures implemented using disposable formworks, including different types of foundation piles and retaining walls; modular elements, called moulds, are also known, each having dimensions substantially smaller than those of the handwork to be realized, by properly composing which formworks of the desired dimensions are made-up.
Disposable moulds are known to build-up small low-cost detached houses, typically but not exclusively for developing countries, formed of containing panels, which are assembled in the building yard to realize formworks designed to internally support the pipes of the hydraulic system and/or the cable ducts of the electrical system, including, for example, MX 2008011228 A or FR 2558868 (A1).
These solutions are uncomfortable in that they need the transportation of big-size elements and are also difficult to install, in that they need skilled and specialized operators to get the necessary alignments and perpendicularities of the moulds.
Ad-hoc special pieces are also necessary to realize doors and windows.
This is the reason why modular disposable moulds have been developed, as shown in FR 2618825, which allow to easily assemble formworks of different shapes and sizes, to realize the openings for doors and similar devices.
These modular disposable moulds are generally designed and developed in such a way as to be assembled together, while leaving ways through from one mould to the other internally thereto.
Thanks to said ways through, the cement mixture can spread from superimposed or partially superimposed modular moulds, as well as between adjacent modular moulds, in such a way as to make the concrete effectively cast internally to the formworks.
Unfortunately, the final appearance of the cement handworks obtained using disposable formworks of this type is very unpleasant, since the formworks, which remain visible; are aesthetically disagreeable and cannot be trimmed, for example by plastering them, because the plaster layer applied onto the outer surface of the formworks tends to come off and fold down, thus giving a very shabby appearance to the just made wall.
Furthermore, modular moulds are very expensive to transport, since the overall volume of the moulds is substantially equal to the overall volume of the finished walls.